Essien played under Mourinho at both Chelsea and Real Madrid, with the midfielder taking to calling Mourinho "Daddy" during their time working together.
The Portuguese paid Lyon £25m for Essien's services back in 2005 during his first spell at Stamford Bridge, before later taking him to the Spanish capital on loan.
Spekaing to Malaysian TV channel 'Astro Supersport', Mourinho gave a glowing endoresment of his former charge.
"He was not my player, he is my son - I am his white daddy," Mourinho explained.
"He was probably the only one who took me to his home, to the real home. To the place he was born, to the street where he played football as a kid.
"He made me fall in love with Ghana, with Accra where he lived, because then I had a better understanding of his mentality."
Meanwhile, the United boss praised the lengths Essien was prepared to go to for his clubs and his team-mates.
"I understand why as a player he was ready for everything, he was ready to die for the fellow players, for the club, for the manager, why he was ready to play like he did for me at Real Madrid with a knee that was not a knee anymore," he added.
"It was a destroyed knee but with that personality, that desire and that mentality he suffered, always he suffered, but always with a smile. Michael smiles a lot."
Essien himself was moved by Mourinho's kind words, saying: "That's kind of emotional. It is very nice, we have a very good relationship. For him to say that about me is very special."